Feed variator for shapers



May 29, 1934. w. F. ZIMMERMANN FEED VARIATOR FDR SHAPERS 2 Sheets-Sheet1 Filed April 21' 1931 gnoemtoz y 1934. w, F. ZIMMERMAN'N 1,960,565

FEED VARIATOR FOR SHAPERS Filed April 21, 1931 2 Sheets-Sheet 2 avwewtoz351 flame/1 A 774M441, 60 4mm Patented May 29, 1934 UNITED STATES PATENTOFFICE FEED VARIATOR FOR SHAPERS Application April 21, 1931, Serial No.531,727

'7 Claims. ((31. 90-38) This invention deals with machine tools, and itrelates more particularly to step-feed mechanisms such as are usedintermittently to shift the work-table of a shaping machine, thereby tocause the reciprocating tool successively to take parallel cuts uponadjacent portions of a work-piece.

To meet the demands of the user of a machine tool of this type, it isdesirable that the 10 feeding mechanism be so coordinated with thestroke of thetoolcarrying ram that thefeed will not be effected duringthe forward or cutting stroke thereof; that the feed mechanism bereadily capable of adjustment, though be not affected by adjustments in'the strokeof the ram; and that the mechanism be devoid of harshmechanical actions so that it will operate quietly, efiiciently andwith. a minimum: amount of wear on the parts.

From the standpoint'of the manufacturer, it is essential that thefeeding mechanism be so designed :that the parts thereof may be builtand assembled at a minimum of expense.

The primary object of this invention is to render available an improvedstep-feed mechanism for shaping machines which will meet all of theabove mentioned desiderata.

This object has been attained by the provision of a feeding mechanismincluding a feed-nut-supported by the work-table and a feed-screwthreaded through said nut and journaled in the-crossrail on which thetable isslidingly mounted. An important feature of the inventionresidesin the improved means'provided for giving to thefeedscrew step-by-steppartial rotations during the return movements of the ram. As inconventional shaping machines, the tool-carrying-ram is given itsrelatively slow forward or cutting stroke and itsrelatively f-astreturnstroke by a suitable swinging lever journaled in the machine frame. Thislever is actuated by a crank-pin adjustably carried by a continuouslyrotating bullwheel also located within the main frame of the machine.Rotation of the bull-wheel is utilized to actuate the improved mechanismwhich gives to the feed-screw itsstep-by-step rotary movements. A feedactuating cam, fixed to the hub of the bull-wheel, engages one arm of atwo armed lever the other arm of which is connected to actuate, througha suitable ratchet-and-pawl mechanism, a forwardly extending shaftgeared to the feed screw. Thus through rotation of the bull-wheel thetable is given its feeding movements. The direction of table movement iscontrolledby a suitable clutch mechanism later to be described. Thefeed-actuating cam acts, upon each rotation, to shift thetwoarmed leverto predetermined extreme position. The amount of successive table feedmovements is determined by the mean position to which said lever ispermitted to move as the high point of the cam recedesfrom the lever.The'means for variably limiting the retractive movement of the lever, sothat the operator readily may vary the feed, constitutes an importantfeature of this invention and will hereinafter be described in detail. 7

A feeding mechanism of this general nature is disclosed in my UnitedStates Patent No. 1,830,309 dated Nov. 3, 1931 of which the presentinvention is an improvement.

Other objects and advantages will be in part indicated in the followingdescription and in part rendered apparent therefrom in connection withthe annexed drawings.

To enable others skilled in the art so fully to apprehend the underlyingfeatures hereof that they may embody the same in the various wayscontemplated by this invention, drawings depicting a preferred typicalconstruction have been annexed as a part of this disclosure and, in suchdrawings, like characters of reference denote corresponding partsthroughout all the views, of which:-

Figure 1 is a side elevation of a shaping machine embodying the presentinvention. Fig. 2 is a vertical section substantially on the line 2-2 ofFig. 1. Fig. 3 is a vertical section substantially on the line 33' ofFig. 4 and Fig. 4 is a horizontal sectionshowi-ng certain of theinteriorelements of the assembled feedmechanism.

Referring more specifically to the drawings, the invention is disclosedas embodied in a shaping machine comprising a main frame formedof a baseA and an upstanding closed housing B supported thereon. Reciprocablymounted on-guideways provided by the upper portion: of the main frame isa tool carrying ram C which carries, at its forward end, the usualcutting tool in a manner common to machine tools of this type. The workto be machined is usually supported upon a suitable table T translatablymounted on .a cross rail R adjustably secured upon the forward face ofthe main frame. Journaled lengthwise of the cross rail is a feed screw Swhich has a threaded engagement with a feed nutN non-rotatably carriedby the work-table. Means later to be described is provided for giving tothe feed screw intermittent rotary movev against the cone 21 by a spring23. the bevel gear 22 to rotate as a unit with the ments thereby toeffect step-by-step feed of the work-table.

Reciprocatory motion is given to the ram by means of conventionalmechanism including a slotted lever L actuated by a crank-pin P carriedby a bull-wheel D, which, in turn, derives motion from a shaft E throughsuitable change gears F. These elements being conventional, detailedillustration and description thereof is deemed unnecessary.

Fixed to the bull-wheel D and rotatably journaled in the main frame ofthe machine is a sleeve-like hub 1, the rotation of which is utilized toactuate the improved intermittent table feed.

To the hub 1 is secured, as by means of a flange 2, a feed actuating cam3 the periphery of which is adapted to engage an arm a of a two-armedlever 4, fulcrumed on a rod 5, sup' ported by a sub-casing 6, securedupon the side of the main frame. A spring 7, having one end connected tothe lever 4 and the other end connected to the main frame, tends toswing the lever counter-clockwise, as viewed in Fig. 3 to cause the arma (or a roller a carried thereby) continuously to bear against theperiphery of the cam. Thus it will be understood that in each rotationof the cam the high point thereof will swing the lever 4 clockwise to anextreme posi tion as shown in Fig. 3. Upon retraction of the high pointof the cam, due to rotation thereof, the arm a of the lever 4 will(through the action of the spring) follow the receding periphery of thecam. From the foregoing it will be understood that unless some means isprovided to limit the retractive movement of the lever it would be giventhe complete throw of the actuating cam.

Oscillatory motion of the lever 4 is utilized 'to effect, in the feedscrew, step-by-step rotary motion and means is provided for limiting themovement of said lever thereby to vary the feed rate, as will now bedescribed.

The arm b of the lever 4 is provided with a gear segment 8 in mesh witha gear 9 rotatably mounted, by means of a bushing 10, on a stub shaft 11journaled in the sub-casing 6. Also journaled on the bushing 10 andkeyed to the hub of the gear 9 is an oscillator 12 which carries aspring-pressed pawl 13 adapted to engage the teeth of a ratchet wheel 14keyed to the shaft 11. Thus oscillation of the lever 4 effects, throughthe gear 9, oscillator 12 and pawl 10, step-by-step rotation of theratchet wheel 14 and the shaft 11 upon which it is secured. To preventthe pawl 10 from pulling the ratchet wheel backwards by friction a pairof spring pressed stop pawls l5 and 16 are maintained in engagement withthe ratchet and prevent retrograde rotation thereof.

Secured upon the forward end of the shaft 11 is a bevel gear 17 whichmeshes with and drives a similar gear 18 fixed upon one end of a sleeve19 telescopically connected to the splined 05 end portion 20 of a shaft20. This shaft has, at its forward end, a cone head 21. A bevel gear 22loosely encircling the shaft 20 has a counter-cone socket which isspring-pressed This causes shaft 20 except in the event of abnormalstrains during which slippage may take place to prevent breaking of theparts. The bevel gear 22 is simultaneously in mesh with reversing bevelgears "24 and 25, which, by means of the usual clutch sleeve 26, may beused to drive the feed screw S which intermittently feeds the table T.To protect the running shafts, a casing 27 is pivoted coaxially aboutthe unthreaded end of the feed screw shaft and telescopes with a casing28 which likewise pivots coaxial with the shaft 11, this arrangementaccommodating the rise and fall of the cross rail at the front of themachine.

From the foregoing it will be seen that stepby-step rotation will betransmitted to the feed screw by rotations of the feed actuating cam 3.

As hereinbefore stated this invention provides novel means for varyingthe rate at which the table is fed under the actuation of the constantthrow feed cam. This is effected by limiting, to any desired extent, theretractive movement of the lever 4 after it has been fully advanced bysaid cam. The improved means for accomplishing that purpose comprises anabutment wall 30 provided by a member 30, in the nature of a sector,pivotally mounted upon the shaft 5 adjacent the oscillating lever 4. Thestop-wall 30 is adapted, during retractive movement of the lever 4,under the influence of the spring '7, to be engaged by a portion of saidlever, or by a stud a carried thereby, to prevent the lever frompartaking of the full throw of the feed cam. To regulate the feed to anydesired rate, manual means is provided for adjusting the member 30 aboutthe rod 5 thereby so to position the stopwall 30 as to arrest the lever4 in its retraction at any desired position in its normal stroke. Thismeans includes a gear 31 in mesh with the teeth of a gear segment 30provided by the member 30. A dial 32, fitted with an actuating lever 33,is fixed to the hub 31 of the gear 31, exteriorly of the sub-casing 6and serves as means to rotate the gear 31 thereby to vary the positionof the abutment 30 The feed effected by any given adjustment of the dialmay be determined by a scale of graduations 32 carried by the dial. Aspring detent 84 carried by the sub-casing 6 maintains the dial and theparts connected therewith in adjusted positions.

Without further analysis, the foregoing will so fully reveal the gist ofthis invention that others can, by applying current knowledge, readilyadapt it for various utilizations by retaining one or more of thefeatures that, from the standpoint of the prior art, fairly constituteessential characteristics of either the generic or specific aspects ofthis invention and, therefore, such adaptations should be, and areintended to be, comprehended within the meaning and range of equivalencyof the following claims:

Having thus revealed this invention, I claim as new and desire to securethe following combinations and elements, or equivalents thereof, byLetters Patent of United States:

1. In a shaping machine having a ram, an adjustable stroke reciprocatortherefor, a table, and a table-feeding transmission; a one-way motiontransmitter for actuating said transmission comprising an actuatorsynchronized with said reciprocator; a two-armed lever fulcrumed on anaxis parallel to the axis of said reciprocator and adapted tobeoscillated thereby, one arm of said lever being adapted to be advancedby said actuator to a predetermined extreme position; a gear segmentformed on the other arm of said lever; a, gear in engagement with andoscillated by said segment; a ratchet and pawl mechanism actuaated bysaid gear and operatively connected to operate said table feedingtransmission; yielding means tending to hold said lever in'engagementwith said actuator; and an adjustable abutment for limiting theretractive movement of said lever under the influence of said yieldingmeans.

2. In a step-feed mechanism for machine tool tables having a rotatablescrew and a non-rotatable nut carried by the table and having a threadedconnection with said screw; means for intermittently giving rotarymovements to said screw, said means comprising a shaft geared to saidscrew; a positive throw rotary element; a two-armed lever having one endmaintained in the path of said rotary element and adapted to be advancedthereby to an extreme position; means to retract said lever after itsadvance by said rotary element; means comprising an adjustably mountedabutment for limiting the retractive movement of said lever; a gearsegment carried by the other arm of said lever; a gear meshing with saidsegment and adapted to be oscillated thereby; and means actuated by saidgear to give step-by-step rotary movements to said shaft.

3. In a shaping machine having a ram and means including a rotarybull-wheel and a lever actuated thereby for reciprocating said ram, atable, and a table-feeding mechanism; a oneway motion transmitter foractuating said table feeding mechanism comprising a cam rotatable withsaid bull-wheel; a two-armed lever fulcrumed intermediate its ends, onearm of said lever being adapted to be advanced by said cam to apredetermined extreme position; a gear segment formed on the other armof said lever; a gear in engagement with said segment; a ratchet andpawl mechanism actuated by said gear and operatively connected with saidtable feeding mechanism; yielding means tending to hold said lever inengagement with said cam; an adjustable member affording an abutment forlimiting the retractive movement of said lever under the influence ofsaid yielding means; a gear segment formed on said member; a gear inmesh therewith; and manual means for rotating said gear to vary theposition of said abutment.

4. In a step-feed mechanism for machine tool tables having a rotatablescrew and a non-rotatable nut carried by the table and having a threadedconnection with said screw; means for intermittently giving rotarymovements to said screw, said means comprising a shaft geared to saidscrew; a rotating cam; a two-armed lever having one end maintained inthe path of said cam and adapted to be advanced thereby to an extremeposition; spring means to retract said lever after its advance by saidcam; means comprising an adjustable element providing an abutment wallfor limiting the retractive movement of said lever; a manuallyadjustable member; a gear connection between said member and saidadjustable element for shifting said abutment wall by movement of saidmember; a gear segment carried by the other arm of said lever; a gearmeshing with said segment and adapted to be oscillated thereby; andmeans actuated by said gear to give step-by-step rotary movements tosaid shaft.

5. In a table feed mechanism having a rotary screw and a cooperating nutcarried by the table; a constant throw rotating feed actuating cam;means for giving to said feed screw step-by-step rotary motions ofvarying amplitude from said constant throw cam, said means including anoscillatory lever fulcrumed intermediate its ends and having one armengaging the periphery of said cam and adapted to be shifted to apredetermined extreme position thereby; yielding means tending to holdsaid arm in engagement with said cam as the periphery thereof recedesfrom said arm; a segment formed on the other arm of said lever; a gearengaging said segment and adapted to be oscillated thereby; means fortransmitting to said feed screw step-by-step rotary movements from theoscillatory movements of said gear; means for limiting the movement ofsaid lever under the influence of said yielding means comprising amember pivoted adjacent the fulcrum of said lever and affording a stopwall adapted to engage said lever and obstruct the retracting movementthereof; a manually adjustable element; and a gear connection betweensaid manually adjustable element and said member for shifting the latterabout its pivot to vary the position of said stop: wall.

6. In a shaping machine having a ram and means including a rotarybull-wheel and a lever actuated thereby for reciprocating said ram, atable, and a table feeding mechanism; a oneway motion transmitter foractuating said table feeding mechanism comprising an actuator rotatablewith said bull-wheel; a two-armed lever fulcrumed intermediate its ends,one arm of said lever being adapted to be advanced by said actuator to apredetermined extreme position; a gear segment formed on the other armof said lever; a gear in engagement with said segment; a ratchet andpawl mechanism actuated by said gear and operatively connected with saidtable feeding mechanism; yielding means tending to hold said lever inengagement with said actuator; an adjustable member affording anabutment for limiting the retractive movement of said lever under theinfluence of said yielding means; a gear seg ment formed on said member;an adjusting gear mounted coaxial with the axis of said actuator andmeshing with the gear segment on said adjustable member; and manualmeans also coaxial with said actuator for rotating said adjusting gearand thereby said adjustable member to vary the position of saidabutment.

7. In a shaping machine having a ram and means including a rotarybull-wheel and a lever actuated thereby for reciprocating said ram, atable, and a table-feeding mechanism; a one-way motion transmitter foractuating said table-feed.- ing mechanism comprising a cam rotatablewith said bull-wheel; a two-armed lever fulcrumed intermediate its ends,one arm of said lever being adapted to be advanced by said cam to apredetermined extreme position; a gear segment formed on the other armof said lever; a gear in engagement with said segment; a ratchet andpawl mechanism actuated by said gear and operatively connected with saidtable feeding mechanism; yielding means tending to hold said lever inengagement with said cam; an adjustable member pivoted coaxial with thefulcrum of said lever and affording an abutment for limiting theretractive movement of said lever under the influence of said yieldingmeans; a gear segment formed on said member; an adjusting gear mountedcoaxial with the axis of said rotatable cam and meshing with the segmenton said adjustable member; and a manually rotatable member arrangedcoaxial with said adjusting gear and operatively connected therewith toshift said gear and its engaged segment thereby to vary the position ofsaid abutment.

WILLIAM F. ZIMMERMANN.

